1. Field of the Invention
The present invention relates to an optical coupling apparatus, in particular, the invention relates to an optical coupling apparatus with a simplified structure and installed in a limited space such as an inside of an optical transceiver.
2. Background Arts
Recent optical communication systems often install a wavelength division multiplexing (WDM) system to enhance the transmission capacity. For instance, optical transceivers following the multi-source agreements (MSA) such as CFP, QSFP (Quadrature Small Form-factor Pluggable), and so on multiplex four optical signals having wavelength grids of, for instance, CWDM (Coarse WDM) and LAN-WDM (Local Area Network WDM), on an optical fiber. Such an optical transceiver installs an optical multiplexer and/or an optical de-multiplexer to multiplex/de-multiplex optical signals optically connected with optical transducers of laser didoes and photodiodes with inner fibers.
When such optical components are connected with the arrangement of the pig-tailed fibers permanently and only one of the optical components shows a failure, all optical components installed within the optical transceiver are inevitably replaced, or at least carrying out procedures of cutting the pig-tailed fiber, replacing the failure optical component, and connecting the inner fiber of the replace component with already installed inner fiber by the fusion splicing. In order to carry out the procedures above, the installed pigtailed fibers are necessary to have surplus lengths, which dis-arranges the inside of the optical transceiver.
Some background arts have reported to connect the inner fibers with inner optical connectors. The inner optical connectors, different from ordinary connectors, are unnecessary to have the moisture resistance, the toughness, the coupling facilitation, and so on. The former two factors are secured by the housing of the optical transceiver. For the last factor, once the inner optical connectors are engaged, the disengagement of the inner connectors is not to be done until the optical components become failure. The simplified structure and the compactness consequence of the simplicity are first requested to the inner optical connector.